Gain excursion & tilt compensation algorithm for TDFA using 1.4 μm/1.5 μm dual wavelength pump control

Summary form only given. We investigated some of the key issues of the amplifier application in WDM systems such as gain tilt and gain excursion, along with their compensating techniques. We explained the gain excursion/tilt behavior of thulium-doped fiber amplifier (TDFA) under 1.4 μm/1.5 μm main/subsidiary pumping scheme. It was found that it is necessary to control both wavelengths to completely compensate the induced gain excursion from the channel add/drops. With coarse tuning on the main pump power for gain level control, together with subsidiary pump power control for gain tilt fine-tuning, it was possible to reduce the gain excursion within 0.1 dB over the entire gain bandwidth, up to 4 dB of gain excursions. Even limited by the experimental set-up, we believe that this algorithm would apply to wider gain excursion values, and can be used to develop a practical gain tilt control algorithm different from that of EDFA.